Development and Progression of Polyneuropathy Over 5 Years in Patients With Type 2 Diabetes

What does nerve ultrasound contribute to the evaluation of diabetic polyneuropathy over time? A prospective follow-up observational study of people with type 2 diabetes

AIMS

Studies using peripheral nerve ultrasound have shown moderate nerve enlargement in individuals with diabetic polyneuropathy (DPN). Neither extent, course, consistency, nor clinical significance of this finding is clear.

METHOD

We examined 156 people with type 2 diabetes mellitus using nerve ultrasound, nerve conduction studies, and clinical scores. 59 received a follow-up examination after one year and 43 patients after two years.

RESULTS

Increase of cross-sectional area (CSA) of the peripheral nerves in DPN was rather negligible compared to normative cut-off values. The CSA of the median nerve at the forearm and wrist and the ulnar nerve at the upper arm, forearm and wrist were significantly larger in individuals with DPN compared to those without DPN. People with DPN had significant changes in most parameters of nerve conduction studies. Ultrasound measurements over time showed a slight increase in CSA in the median nerve at the carpal tunnel and a slight decrease in the fibular nerve at the fibular head. Ultrasound pattern sum score slightly decreased in the DPN group over two years.

CONCLUSIONS

Ultrasound measurements alone may be insufficient to detect DPN. Follow up with nerve ultrasound over one or two years was short and did not show substantial changes.

The global and regional burden of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is length-dependent peripheral nerve damage arising as a complication of type 1 or type 2 diabetes in up to 50% of patients. DPN poses a substantial burden on patients, who can experience impaired gait and loss of balance, predisposing them to falls and fractures, and neuropathic pain, which is frequently difficult to treat and reduces quality of life. Advanced DPN can lead to diabetic foot ulcers and non-healing wounds that often necessitate lower-limb amputation. From a socioeconomic perspective, DPN increases both direct health-care costs and indirect costs from loss of productivity owing to neuropathy-related disability. In this Review, we highlight the importance of understanding country-specific and region-specific variations in DPN prevalence to inform public health policy and allocate resources appropriately. We also explore how identification of DPN risk factors can guide treatment and prevention strategies and aid the development of health-care infrastructure for populations at risk. We review evidence that metabolic factors beyond hyperglycaemia contribute to DPN development, necessitating a shift from pure glycaemic control to multi-targeted metabolic control, including weight loss and improvements in lipid profiles.